docs: def utc2et(utcstr):
      """
      Convert an input time from Calendar or Julian Date format, UTC,
      to ephemeris seconds past J2000.
  
      http://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/cspice/utc2et_c.html
  
      :param utcstr: Input time string, UTC. 
      :type utcstr: str
      :return: Output epoch, ephemeris seconds past J2000.
      :rtype: float
      """
      utcstr = stypes.stringToCharP(utcstr)
      et = ctypes.c_double()
      libspice.utc2et_c(utcstr, ctypes.byref(et))
      return et.value